/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.config;

import org.apache.log4j.Appender;
import org.apache.log4j.Category;
import org.apache.log4j.Level;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * Prints the configuration of the log4j default hierarchy (which needs to be
 * auto-initialized) as a propoperties file on a {@link PrintWriter}.
 * 
 * @author Anders Kristensen
 */
public class PropertyPrinter implements PropertyGetter.PropertyCallback {
	protected int numAppenders = 0;
	protected Hashtable appenderNames = new Hashtable();
	protected Hashtable layoutNames = new Hashtable();
	protected PrintWriter out;
	protected boolean doCapitalize;

	public PropertyPrinter(PrintWriter out) {
		this(out, false);
	}

	public PropertyPrinter(PrintWriter out, boolean doCapitalize) {
		this.out = out;
		this.doCapitalize = doCapitalize;

		print(out);
		out.flush();
	}

	protected String genAppName() {
		return "A" + numAppenders++;
	}

	/**
	 * Returns true if the specified appender name is considered to have been
	 * generated, that is, if it is of the form A[0-9]+.
	 */
	protected boolean isGenAppName(String name) {
		if (name.length() < 2 || name.charAt(0) != 'A')
			return false;

		for (int i = 0; i < name.length(); i++) {
			if (name.charAt(i) < '0' || name.charAt(i) > '9')
				return false;
		}
		return true;
	}

	/**
	 * Prints the configuration of the default log4j hierarchy as a Java
	 * properties file on the specified Writer.
	 * 
	 * <p>
	 * N.B. print() can be invoked only once!
	 */
	public void print(PrintWriter out) {
		printOptions(out, Logger.getRootLogger());

		Enumeration cats = LogManager.getCurrentLoggers();
		while (cats.hasMoreElements()) {
			printOptions(out, (Logger) cats.nextElement());
		}
	}

	protected void printOptions(PrintWriter out, Category cat) {
		Enumeration appenders = cat.getAllAppenders();
		Level prio = cat.getLevel();
		String appenderString = (prio == null ? "" : prio.toString());

		while (appenders.hasMoreElements()) {
			Appender app = (Appender) appenders.nextElement();
			String name;

			if ((name = (String) appenderNames.get(app)) == null) {

				// first assign name to the appender
				if ((name = app.getName()) == null || isGenAppName(name)) {
					name = genAppName();
				}
				appenderNames.put(app, name);

				printOptions(out, app, "log4j.appender." + name);
				if (app.getLayout() != null) {
					printOptions(out, app.getLayout(), "log4j.appender." + name
							+ ".layout");
				}
			}
			appenderString += ", " + name;
		}
		String catKey = (cat == Logger.getRootLogger())
				? "log4j.rootLogger"
				: "log4j.logger." + cat.getName();
		if (appenderString != "") {
			out.println(catKey + "=" + appenderString);
		}
		if (!cat.getAdditivity() && cat != Logger.getRootLogger()) {
			out.println("log4j.additivity." + cat.getName() + "=false");
		}
	}

	protected void printOptions(PrintWriter out, Logger cat) {
		printOptions(out, (Category) cat);
	}

	protected void printOptions(PrintWriter out, Object obj, String fullname) {
		out.println(fullname + "=" + obj.getClass().getName());
		PropertyGetter.getProperties(obj, this, fullname + ".");
	}

	public void foundProperty(Object obj, String prefix, String name,
			Object value) {
		// XXX: Properties encode value.toString()
		if (obj instanceof Appender && "name".equals(name)) {
			return;
		}
		if (doCapitalize) {
			name = capitalize(name);
		}
		out.println(prefix + name + "=" + value.toString());
	}

	public static String capitalize(String name) {
		if (Character.isLowerCase(name.charAt(0))) {
			if (name.length() == 1 || Character.isLowerCase(name.charAt(1))) {
				StringBuffer newname = new StringBuffer(name);
				newname.setCharAt(0, Character.toUpperCase(name.charAt(0)));
				return newname.toString();
			}
		}
		return name;
	}

	// for testing
	public static void main(String[] args) {
		new PropertyPrinter(new PrintWriter(System.out));
	}
}
